Using concat with an int? (java)

Question

I am trying to do the following:

If a number between 1 and 100 is entered by the user, then:

Print out each ordinal from 1 to the given number.

Example below is for the input value of 25:

1st
2nd
3rd
4th
5th
6th
7th
8th
9th
10th
11th
12th
13th
14th
15th
16th
17th
18th
19th
20th
21st
22nd
23rd
24th
25th

I can't figure out how to add the: st, nd, rd, th without using concat.

Here is my code:

import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner scnr = new Scanner(System.in);

   int userNum;
  userNum = scnr.nextInt();
  for (int i=1; i<=userNum; i++) {
  System.out.println(i);
    }
  }
}

Is there another way to do this? Thanks.

Possible duplicate of [Is there a way in Java to convert an integer to its ordinal?](https://stackoverflow.com/questions/6810336/is-there-a-way-in-java-to-convert-an-integer-to-its-ordinal) — lealceldeiro, Oct 22 '18 at 19:45
You cannot concat an Integer at once. [String.concat](https://docs.oracle.com/javase/10/docs/api/java/lang/String.html#concat(java.lang.String)) takes a `String`as parameter. So you have to convert an Integer to `String` first. — LuCio, Oct 22 '18 at 19:52
See [How to concatenate int values in java?](https://stackoverflow.com/questions/2674707/how-to-concatenate-int-values-in-java) — LuCio, Oct 22 '18 at 19:54
If all you're after is to **print** the results, you needn't resort to either `String.concat` or `+`: print the number with `System.out.print` (_not_ `println`), then print the suffix with `System.out.println`. — Kevin Anderson, Oct 23 '18 at 00:12

score 1 · Answer 1 · answered Oct 22 '18 at 20:30

The special String concatentation operator (+) in Java will automatically convert scalars to strings (when the string is on the left). You could do something like this:

System.out.println(""+i+getPostfix(i));

where getPostfix would return an appropriate postfix for the given integer (-st, -nd, etc). I leave implementation of this function as an exercise.

th3matr1x · Answer 2 · 2018-10-22T21:00:27.800

1

you can do that with printf

for (int i=1; i<=userNum; i++) {
     System.out.printf("%d%s\n",i,i%10==1 && i>19 ? "st " : i%10==2 && i>19 ? "nd " : i%10==3 && i>19 ? "rd " : "th ");
}

edited Oct 22 '18 at 21:00

answered Oct 22 '18 at 20:36

th3matr1x

19
5

This is really close but it results with the 11, 12, and 13 being 11st, 12nd, and 13rd. – Lily Morris Oct 22 '18 at 20:50
that was a quick answer, you could elaborate for the rest. i've updated the code for your convienience :) – th3matr1x Oct 22 '18 at 21:00

sare3th · Answer 3 · 2018-10-22T20:53:27.550

You can do it without using concat. You can check if number -st -nd -rd with modulo ( % 10)

import java.util.*;
import java.util.AbstractMap.SimpleEntry;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import java.util.stream.Stream;

public class Main {

private static final String DEFAULT_POSTFIX = "th";
private static final Map<Integer, String> POSTFIX_MAP =
        Stream.of(
                new SimpleEntry<>(1, "st"),
                new SimpleEntry<>(2, "rd"),
                new SimpleEntry<>(3, "nt"))
                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));

private static String getPostfix(int number) {
    if (Arrays.asList(11,12,13).contains(number)) return DEFAULT_POSTFIX;
    return Optional
            .ofNullable(POSTFIX_MAP.get(number % 10))
            .orElse(DEFAULT_POSTFIX);
}

public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    int userNum = scanner.nextInt();
    IntStream
            .rangeClosed(1, userNum)
            .forEach(it -> System.out.println(it + getPostfix(it)));
}

}

maybe, but she works with numbers between 1 to 100 (from the question) — sare3th, Oct 22 '18 at 21:10

Using concat with an int? (java)

3 Answers3